UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL   EXPERIMENT  STATION 
COLLEGE  OF  AGRICULTURE  "NJ-  ,DE  WHEELER'  '"••«" 

THOMAS   FORSYTH    HUNT,    Dean  and  Director 

BERKELEY  H.    E.   VAN    NORMAN,   vice-Director    and    Dean 

»  University  Farm  School 


CIRCULAR  No.  174 
September,  1917 


FARM  DRAINAGE  METHODS' 

By  WALTER  W.  WEIR, 
Senior  Drainage  Engineer,  U.  S.  Department  of  Agriculture 


This  circular  is  intended  for  use  only  in  sections  of  the  state  which  are  free 
from  alkali;  it  is  not  applicable  to  irrigated  land. 

CONTENTS  PAGE 

Introduction     2 

The  Need  for  Drainage 2 

Effects    of    Drainage 2 

Open  Drains  4 

When  Open  Drains  are  necessary 4 

Objections  to  Open  Drains 5 

Importance  of  Engineering  Assistance 5 

Outlets   6 

Design   of  Open   Drains 7 

Methods  of  Construction 9 

Maintenance 9 

Underdrains    10 

Design    of    Underdrains 10 

Use  of  Soil  Auger 10 

Grade    11 

Depth 11 

Spacing    12 

Size    of    Tile 13 

Kinds  of  Tile 15 

Construction    of   Underdrains 16 

Laying  out  the  Drain 16 

Ditching  Tools  and  Machinery 17 

Digging    to    Grade 19 

Laying   Tile   21 

Backfilling  23 

Box  Drains  23 

Surface  Inlets,  Silt  Boxes,  and  Outlets 24 

Maintenance  of  Tile  Drains 25 

Cost  of  Tile  Drainage 28 

Vertical    Drainage 29 

Co-operation    in    Drainage 30 

1  This  circular  was  prepared  under  a  co-operative  agreement  between  the 
Office  of  Public  Roads  and  Rural  Engineering,  U.  S.  Department  of  Agriculture, 
and  the  University  of  California,  Agricultural  Experiment  Station. 


INTRODUCTION 

The  purposes  of  this  circular  are  to  call  attention  to  the  need  for 
drainage  on  many  of  the  California  farms  which  are  located  in  regions 
where  -the  annual  rainfall  is  sufficient  for  agricultural  purposes ;  to 
outline  the  advantages  to  be  derived  from  drainage;  to  recommend 
the  use  of  tile  and  the  systematic  construction  of  open  drains;  to 
offer  suggestions  regarding  the  spacing,  depth,  and  size  of  drains,  as 
well  as  methods  and  cost  of  installing  them;  and  to  urge  better  co- 
operation between  the  owners  of  adjoining  farms  in  the  disposal  of 
storm  water  and  surface  run-off. 

THE   NEED   FOR   DRAINAGE 

The  average  annual  rainfall  in  the  state  varies  from  more  than  fifty 
inches  in  portions  of  Del  Norte,  Humboldt,  and  Mendocino  counties 
and  the  northern  high  Sierras  to  less  than  ten  inches  over  most  of 
Imperial,  San  Bernardino,  Eiverside,  and  Inyo  counties  and  the  San 
Joaquin  Valley.  Most  of  the  Sacramento  Valley  and  the  coast  region 
south  of  San  Francisco  receive  an  annual  rainfall  of  from  ten  to 
twenty  inches.  Figure  1  shows  the  distribution  of  the  rain  over  the 
state.  A  very  large  proportion  of  the  total  annual  rainfall  occurs 
during  December,  January,  February,  and  March. 

The  sections  which  receive  twenty  inches  or  more  of  rainfall  have 
a  tendency  to  become  too  wet  for  proper  cultivation  during  certain 
periods.  Generally  the  heavier  soils  which  do  not  absorb  water 
rapidly  and  which  are  most  in  need  of  drainage  are  found  on  the 
flatter  valley  floors  or  in  depressions.  Almost  every  farm  has  some 
place  where  the  water  stands  too  long  after  a  rain,  causing  a  partial 
or  total  failure  of  crop.  Other  places  remain  too  wet  for  plowing 
and  can  not  be  seeded  when  the  rest  of  the  field  is  ready.  These  spots 
must  be  plowed  and  seeded  later  or  be  left  uncropped.  In  either 
case,  there  will  be  an  added  expense  or  a  material  loss  in  crops.  The 
saving  of  this  expense  may  not  seem  important  during  any  one  year, 
but  when  the  damage  is  continually  recurring  it  assumes  considerable 
significance. 

EFFECTS   OF  DRAINAGE 

In  addition  to  the  obvious  benefits  obtained  by  removing  excess 
water  and  reclaiming  swampy  areas  so  that  they  may  be  profitably 
cultivated,  drainage  has  other  marked  effects  upon  the  soil.  Some 
of  the  most  important  benefits  thus  derived  are  as  follows : 

Drainage  improves  the  granulation  or  tilth  of  the  soil.  This  is 
accomplished  through  the  removal  of  the  excess  water  quickly  after 


rains,  thus  preventing  the  puddling  or  running  together  of  the  soil 
mass.  Even  a  stiff  clay  soil  is  rendered  more  porous  and  granular 
by  the  alternate  drying  and  wetting  which  accompanies  a  properly 
drained  soil  condition. 


SCALE 

0-/O  /nches 
fO-20  /nches 
20-30  inches 
30-40  inches 
40-50  inches 
over50  inches 


\ 


CALIFORNIA 

Average  Annual   Rainfall 

Based  on  Records  for  30  years  Y^W^-'A  ';        goo.— 

Fig.  1. — Distribution  of  average  annual  rainfall  in  California. 


Drainage  improves  the  aeration  of  the  soil.  As  the  excess  water 
passes  out  of  the  soil,  air  is  drawn  in.  This  aeration  or  ventilation 
promotes  the  growth  of  desirable  micro-organisms,  improves  the  con- 
ditions for  root  growth  and  development,  and  accelerates  oxidation 
and  the,  other  chemical  reactions  that  liberate  and  make  available  the 
plant  food  elements. 


Drainage  improves  the  soil  temperature.  In  poorly-drained  soils 
the  heat  which  should  be  applied  to  warming  the  soil  and  bringing  it 
to  the  proper  temperature  for  the  germination  of  seeds  is  used  in 
evaporating  the  water ;  the  soil  thus  remains  cold.  If  the  excess  water 
be  removed  the  soil  is  warmed  much  sooner,  thus  both  cultivation  of 
the  soil  and  crops  can  be  started  earlier  in  the  spring.  This  is  a 
very  important  consideration  where  it  is  desirable  to  have  crops  as 
far  advanced  as  possible  before  the  dry  summer  season  arrives. 

Thorough  drainage  lessens  the  effect  of  drought.  Only  the  excess 
water  or  free  water  is  removed  by  the  drains.  For  most  plants  the 
only  water  that  is  of  use  remains  in  the  soil  as  a  film  wetting  the 
surface  of  the  grains.  The  removal  of  the  free  water  enables  the 
roots  to  grow  deeply  into  the  moist  soil  and  this  more  extensive  root- 
ing system,  touching  a  large  soil  area,  has  a  much  greater  supply  of 
film  water  to  draw  upon  and  to  carry  the  plant  through  a  period  of 
drought.  This  is  an  important  consideration  in  California,  as  the 
plant  should  be  as  far  advanced  as  possible  before  the  long  dry  season 
approaches. 

OPEN    DRAINS 

Open'  drains,  or  ditches,  may  vary  in  size  from  shallow  furrows 
only  a  few  feet  in  length,  to  deep,  wide  dredged  ditches  many  miles 
in  length.  The  only  type  of  drains  here  discussed,  however,  is  that 
suited  to  the  individual  farm  or  to  a  project  comprising  but  a  few 
small  farms. 

WHEN  OPEN  DRAINS  ARE  NECESSARY 

Open  drains  are  generally  used  as  outlets,  both  for  tile  and  for 
other  open  drains.  When  the  quantity  of  water  to  be  carried  becomes 
such  that  it  is  not  feasible  to  carry  it  underground  in  covered  drains, 
the  use  of  open  ditches  becomes  essential.  The  point  at  which  this 
necessity  occurs  will,  of  course,  depend  almost  entirely  upon  local 
conditions. 

It  is  often  not  feasible  to  design  covered  drains  of  the  size  required 
to  care  for  the  large  quantity  of  surface  water  which  follows  a  storm. 
In  such  cases  open  drains  are  essential.  Again,  where  there  is  con- 
siderable danger  of  tile  drains  becoming  filled  with  sediment  or  becom- 
ing obstructed  in  other  ways,  open  drains  are  the  more  satisfactory. 
It  is  true  that  under  these  conditions  open  drains  may  also  become 
obstructed,  but  they  can  be  cleaned  and  repaired  much  more  easily 
than  can  covered  drains.  Probably  the  most  desirable  feature  of 
the  open  drain  is  the  lower  initial  cost  of  its  construction  as  compared 
with  that  of  the  covered  drain. 


OBJECTIONS  TO  OPEN  DKAINS 

Open  drains  are  objectionable  in  that  when  they  are  deep  enough 
to  thoroughly  drain  the  land  they  are  of  such  width  as  to  become  an 
inconvenience  in  the  field.  Ditches  are  much  more  expensive  to  main- 
tain than  are  covered  drains.  The  unavoidable  roughness  of  the 
sides  and  bottom  of  a  ditch  causes  sediment  to  be  deposited  and  drain- 
age is  thereby  impaired.  Weeds  and  brush  collect  in  ditches  and 
must  be  removed  frequently  if  drainage  is  to  be  maintained.  If  the 
fall  of  an  open  drain  is  too  great  the  water  causes  the  banks  to  erode 
and  cave. 

Open  drains  waste  not  only  the  land  which  they  occupy,  but  the 
land  along  their  banks  which  they  prevent  from  being  cultivated. 
Even  a  comparatively  small  ditch,  with  its  waste  banks,  may  easily 
render  uncultivable  a  strip  of  land  fifty  feet  wide.  Such  a  drain 
requires  over  six  acres  for  each  mile  in  length,  whereas  this  land  is 
saved  to  cultivation  where  covered  drains  are  used.  Weeds  which 
grow  upon  the  ditch  banks  are  unsightly  and  difficult  to  eradicate; 
they  harbor  undesirable  insects  and  animals,  as  well  as  plant  diseases. 
Open  drains  necessitate  bridges  for  crossing,  and  they  cut  fields  into 
irregular  shapes,  making  cultivation  mor  difficult.  The  presence  of 
ditches  in  small  fields  make  it  impractical  to  use  certain  heavy  farm 
machinery.  Except  in  that  they  more  readily  take  care  of  surface 
water,  open  ditches  are  not  as  efficient  as  underdrains ;  the  sides  are 
more  likely  to  become  puddled  and  the  lateral  movement  of  the  ground 
water  retarded. 


IMPOETANCE  OF  ENGINEEKING  ASSISTANCE 
A  drain  should  not  be  constructed  without  first  obtaining  levels 
over  the  line  and  establishing  a  definite  grade,  bottom  width,  and 
side  slopes.  If  this  is  not  done  there  will  be  difficulty  in  maintaining 
uniformity  in  grade  and  the  drain  may  become  congested  at  points 
where  irregularities  occur.  The  importance  of  reliable  engineering 
assistance  in  designing  and  constructing  large  ditches  is  seldom  ques- 
tioned, but  many  small  farm  drains  are  dug  without  any  engineering 
assistance  whatever.  This  practice  should  be  discouraged,  especially 
if  the  farmer  himself  is  not  familiar  with  the  fundamental  principles 
of  stream  flow  and  the  use  of  the  engineer's  level.  A  careful  engineer 
will  make  a  survey,  not  only  of  the  surface  to  determine  the  fall, 
alignment,  etc.,  but  he  will  make  frequent  borings  into  the  soil  to 
determine  the  subsoil  conditions.  California  soils  and  subsoils  are 
often  quite  variable  within  short  distances.      A  knowledge  of  subsoil 


r 


conditions  frequently  is  a  great  aid  in  determining  such  important 
matters  as  depth,  spacing,  and  shape  of  drains. 

Figure  2  illustrates  the  various  types  of  drainage  systems.  One 
would  hardly  expect  to  find  complete  drainage  by  open  ditches  follow- 
ing the  "gridiron"  or  "herringbone"  systems  in  which  the  drains 
follow  a  regular  system  of  parallel  lines  with  definite  spacing  between. 
Such  a  system  would  so  interfere  with  cultivation  as  to  make  it  im- 
practicable. Probably  the  greater  part  of  our  land  to  be  drained 
by  open  ditches,  except  as  the  latter  are  used  for  outlets,  would  require 
the  natural  or  irregular  system  which  follows  the  natural  depressions 
in  the  surface  and  seeks  only  to  remove  water  from  the  low  places  or 
to  divert  or  collect  storm  waters. 


Natural   System 


Intercepting   System 


1  Y 
!  r- 

i  Y' 

I) 


Gridiron   System 


If 

Herring   Bone  System 


Fig. 


-Illustrating  arrangements  of  drains. 


OUTLETS 

The  outlet  is  the  first  consideration  in  drainage.  When  the  outlet 
is  to  be  in  a  stream,  creek,  or  natural  watercourse,  one  must  determine 
whether  the  outlet  is  adequate ;  that  is,  whether  at  times  when  drain- 
age is  most  essential  it  is  capable  of  carrying  the  added  water  from 
the  drain,  and  whether  the  outlet  is  deep  enough  to  insure  proper 
drainage  to  the  fields  which  it  is  proposed  to  drain.  Outlets  are 
sometimes  used  when  it  is  known  that  for  short  periods  after  a  storm 
they  will  be  overtaxed.  Such  a  condition  is  not  desirable  but  often 
it  can  not  well  be  overcome.  If  the  outlet  is  to  be  a  ditch  on  another 
man's  property,  one  should  obtain  the  right  to  use  it  either  by  pur- 
chase or  otherwise.  When  it  is  not  possible  to  obtain  a  gravity  outlet, 
pumping  is  sometimes  resorted  to  and  the  water  disposed  of  through 
channels  whose  elevation  is  higher  than  the  drainage  depth. 


In  rolling  land,  an  outlet  is  usually  easy  to  obtain,  but  on  the 
natter  lands  one  should  not  attempt  to  determine  the  sufficiency  of 
an  outlet  "by  eye,"  and  the  use  of  an  engineer's  instrument  is 
necessary.  An  outlet  to  be  satisfactory  must  have  the  drain  discharge 
freely  into  it. 

DESIGN  OF  OPEN  DRAINS 

For  areas  up  to  160  acres,  drains  in  the  humid  sections  of  Cali- 
fornia should  be  designed  to  remove  about  one  surface  inch2  from  the 
tract  in  twenty-four  hours.  If  water  reaches  the  tract  from  other 
sources,  the  entire  contributing  area  should  be  considered  rather  than 
merely  the  area  it  is  proposed  to  drain.  For  larger  areas  the  run-off 
may  be  decreased  to  three-fourths  inch  in  twenty-four  hours.  Con- 
ditions of  tilth,  topography,  and  soil  are  determining  factors  in  the 
rapidity  and  amount  of  run-off.  In  a  field  in  good  tilth  and  of  gentle 
slopes  the  soil  will  retain  much  more  water  than  in  barren  fields  or 
in  those  having  greater  slopes.  The  size  of  ditch  required  to  carry 
a  given  amount  of  water  is  dependent  upon  the  slope  or  grade  and, 
to  a  less  extent,  upon  the  shape  of  its  cross-section;  the  shape  is 
determined  with  reference  to  the  kind  of  soil  through  which  the  ditch 
passes. 

An  open  drain  should  be  both  deep  and  wide  enough  to  carry  the 
maximum  flow  without  overtopping  its  banks,  and  to  carry  the  normal 
flow  well  below  the  general  ground  surface.  The  banks  of  the  ditch 
should  be  sloped  to  such  an  extent  as  to  prevent,  as  far  as  possible, 
any  caving  when  they  are  wet.  In  clay  the  side  slopes  may  be  as 
steep  as  one-half  foot  horizontal  to  one  foot  vertical,  while  in  sandy 
soils  it  may  be  necessary  to  make  the  slopes  as  flat  as  two  feet  hori- 
zontal to  one  foot  vertical.  The  excavated  material  should  be  placed 
some  distance  from  the  edge  in  order  to  prevent  it  from  slipping  back 
into  the  drain.  A  safe  rule  to  follow  for  ditches  under  twenty  feet 
in  top  width  is  to  place  excavated  material  so  that  the  berm,  or  dis- 
tance from  the  edge  of  the  ditch  to  the  toe  of  the  waste  bank,  is  equal 
to  one-half  the  top  width  of  the  ditch.  The  ditch  shown  in  figure  3 
has  sloping  banks,  and  a  wide  berm  is  left  between  the  ditch  and 
the  waste  bank.  All  of  the  excavated  material  is  in  this  case  placed 
on  one  side  of  the  ditch. 

Rather  shallow  surface  ditches  can  be  dug  satisfactorily  with  teams 
where  the  ground  is  firm  enough  to  permit  teams  going  upon  it.  Team 
and  scraper  ditches  are  sometimes  used  where  surface  water  accumu- 

2  "Inch"  as  used  in  this  paper  means  1/12  of  a  foot  and  must  not  be  confused 
with  the  term  "miner's  inch,"  frequently  used  in  California  by  mining  and 
irrigation  interests. 


8 

lates  in  considerable  quantities  and  the  drain  is  required  simply  to 
remove  it  quickly.  Drains  of  this  nature  are  expected  to  be  dry  most 
of  the  time  and  are  so  dug  as  to  be  of  least  hindrance  to  cultivation 
and  cropping.  In  many  cases  cultivation  is  continued  over  such 
drains. 

Open  drains  dug  by  hand  are  necessarily  limited  to  rather  small 
ditches,  seldom  over  three  or  four  feet  wide  on  top  and  four  or  five 
feet  deep.  Ditches  of  this  type  are  of  much  less  inconvenience  when 
located  along  fence  or  property  lines  than  when  located  through  a 
field. 


Fig.  3. — Construction  of  an  open  drain  by  machinery,  Marin  County,  Cal. 


Drains  to  which  stock  have  access  should  have  slopes  so  flat  that 
they  can  be  entered  without  damage  to  the  drain  or  injury  to  the 
stock.  Figure  4  shows  a  type  of  hand-dug  open  drain  suitable  for  a 
heavy  soil. 

The  banks  of  open  drains,  at  the  points  where  surface  water  enters, 
must  be  protected  so  as  to  prevent  erosion  which  not  only  destroys 
the  banks  and  wastes  land,  but  also  fills  up  the  drain  and  impairs  its 
efficiency.  Surface  water  may  be  admitted  to  an  open  drain  through 
a  box  or  culvert  under  the  waste  bank.  When  properly  constructed, 
such  a  box  will  be  a  protection  to  the  ditch  bank  against  washing. 


METHODS  OF  CONSTEUCTION 
Open  drains  for  the  farm  are  constructed  in  three  ways:  by 
machinery,  with  teams  and  scrapers,  and  by  hand.  There  are  several 
types  of  excavating  machinery  for  digging  open  drains;  these  vary 
in  size  from  the  large  floating  dredge  capable  of  excavating  drains 
up  to  100  or  more  feet  in  width,  to  the  excavator  which  will  dig  a 
drain  three  or  four  feet  in  width.  For  farm  drains,  however,  only 
the  smaller  types  of  excavators  are  used  and  these  only  by  the  larger 
farms  or  by  several  farms  adjoining  in  a  general  plan  of  drain- 
age. Figure  3  shows  an  open  drain  being  constructed  with  power 
machinery,  in  Marin  County,  California.  When  drains  are  con- 
structed during  the  dry  season,  teams  may  be  used.  Ditches  excavated 
in  this  way  are  necessarily  limited  to  rather  shallow,  broad  drains 


"■■ ,-. 


(mMm^*  Bern,  ,._.  M0M 


Fig.  4. — Type  of  hand-dug  ditch  suitable  for  heavy  soils. 


in  soils  stable  enough  to  permit  the  driving  of  teams  over  them. 
Under  certain  conditions  and  for  certain  types  of  drain,  this  method 
is  both  cheap  and  efficient.  Digging  drains  by  hand  is  feasible  only 
when  they  are  small  enough  to  allow  the  excavated  material  to  be 
disposed  of  without  rehandling. 

MAINTENANCE 
Open  ditches  require  a  considerable  expenditure  for  maintenance. 
It  is  this  item  that  makes  the  final  cost  of  open  drains  equal  to  or 
above  that  of  underdrains.  In  order  to  maintain  the  efficiency  of  a 
ditch,  it  is  necessary  to  clean  it  at  least  once  each  year.  Brush  and 
weeds  that  are  certain  to  grow  during  the  dry  season  must  be  removed, 
caving  banks  must  be  repaired,  and  all  obstructions  such  as  temporary 
fences,  rubbish,  etc.,  removed  before  the  wet  season  begins.  After  a 
year  or  two  it  may  be  necessary  to  deepen  the  drain  in  order  to 


10 

maintain  the  desired  depth.  If  these  things  are  not  done  it  will  not 
be  long  before  conditions  will  become  as  bad  as  they  were  before 
the  ditch  was  constructed.  The  cost  of  maintenance  of  course  varies 
with  the  amount  of  excavation  and  repair  work  necessary;  in  a  few 
years  it  may  amount  to  a  considerable  proportion  of  the  first  cost. 

UNDERDRAINS 

Underdrains  represent  the  ideal  method  of  reclaiming  wet  or 
swamp  areas.  They  may  consist  of  tile  or  of  wooden  box-drains,  and 
are  covered  with  soil  so  that  they  do  not  interfere  with  cultivation. 
There  is  little  danger  of  properly  constructed  tile  drains  becoming 
obstructed,  and  consequently  they  require  little  or  no  maintenance. 
Tile  drains  are  permanent,  and  although  the  initial  expense  may  be 
in  excess  of  that  for  open  drains  they  are,  in  the  end,  cheaper  and 
better. 

The  two  general  systems  of  drainage  heretofore  described — the 
regular  and  the  natural — apply  to  underdrains  and  each  system  is 
capable  of  greater  variation  when  tile  are  used.  Figure  2  shows 
some  of  the  variations  possible.  Unless  the  slopes  are  quite  uniform, 
combinations  of  the  various  systems  are  often  used. 

DESIGN  OF  UNDEEDKAINS 
Use  of  Soil  Auger: 

The  soil  auger  is  one  of  the  tools  most  frequently  used  by  the 
careful  drainage  engineer.  Figure  5  shows  a  soil  auger  of  the  type 
commonly  employed.  This  auger  consists  of  a  li/^-mch  carpenter's 
auger  welded  to  a  i/^-inch  rod  which  by  the  insertion  of  additional 
sections  can  be  extended  to  six  feet  or  more.  The  point  of  the  auger 
should  be  filed  away  so  as  to  make  a  straight  cutting  edge  and  the 
points  of  the  worm  should  be  bent  downward  to  facilitate  cutting 
into  very  hard  soil.  Subsoil  conditions,  as  for  instance  the  presence 
or  absence  of  hardpan,  gravel,  or  clay  strata,  have  a  marked  bearing 
on  the  location,  depth,  and  spacing  of  drains.  Borings  with  a  soil 
auger  will  quickly  determine  the  true  subsoil  conditions. 

The  drainage  of  land  which  is  wet  from  springs  often  requires  a 
great  deal  of  care  in. the  selection  of  the  proper  locations  for  the 
drains.  It  is  essential  that  the  exact  locations  of  the  springs  be 
determined  so  that  the  drains  shall  intercept  the  water  before  it  has 
spread  through  the  surrounding  soil.  When  a  considerable  area  has 
become  saturated  by  springs  it  may  be  difficult  to  determine  their 
exact  locations,  but  the  matter  is  of  sufficient  importance  to  justify 
considerable  effort  to  locate  them  accurately.     The   depth,  spacing 


11 


(if  more  than  one  is  required),  and  size  of 
drain  required  for  springy  land  must  be 
determined  for  each  individual  case  and 
the  information  is  often  most  easily 
obtained  by  a  diligent  use  of  the  soil  auger. 

Grade : 

Other  things  being  equal,  the  more  fall 
that  can  be  obtained  for  a  tile  line,  the 
better  and  more  rapid  will  be  the  drainage. 
A  fall  of  one  foot  per  thousand  feet  is 
about  as  little  as  it  is  advisable  to  use, 
although  many  successful  tile  drains  have 
less.  The  greater  the  fall,  the  greater  will 
be  the  carrying  capacity  of  the  drain  or 
the  smaller  the  drain  required  to  carry  a 
given  quantity  of  water.  Too  much  em- 
phasis can  not  be  laid  on  the  necessity  for 
accurately  determining  by  means  of  engi- 
neering instruments,  the  available  fall,  the 
grade  upon  which  the  drain  is  to  be  laid, 
and  the  sufficiency  of  the  outlet,  Figure  6 
shows  tile  on  grade  lines  which  have  been 
correctly  and  incorrectly  determined. 
Wherever  it  is  possible  to  do  so,  the  grade 
should  be  made  steeper  as  the  outlet  is  ap- 
proached. Such  a  condition  is  a  reasonable 
assurance  that  the  drains  will  not  become 
clogged  by  particles  of  soil  settling  in  the 
tile  lines. 

Depth: 

The  depth  to  which  tile  should  be  laid 
is  variable.  In  sandy  soils  tile  may  be 
placed  deeper  than  in  clay  soils,  because 
in  the  former  the  water  more  freely  pene- 
trates the  soil  and  consequently  reaches  the 
tile  lines  more  readily.  In  heavy  clay  soils 
percolation  is  slow,  and  if  drains  are  placed 
too  deep  the  water  may  not  reach  the  tile 
rapidly  enough  to  make  the  drain  efficient. 
Generally  speaking,  the  greater  the  depth 
to  which  the  soil  can  be  completely  drained, 
the  more  efficient  the  system  will  be.  Sandy 


a 


a 


Fig.  5. — Soil  auger. 


12 

or  sandy-loam  soils  usually  require  drains  placed  about  four  to  six 
feet  deep,  while  in  clay  loams  and  clay,  drains  placed  three  to  three 
and  a  half  feet  deep  may  prove  more  efficient.  Experiments  indicate 
that  about  three  feet  should  be  the  minimum  depth  for  tile,  even  in 
clay  soils. 
Spacing : 

The  proper  spacing  of  drains  depends  to  a  considerable  extent 
upon  the  depth.  The  lateral  movement  of  water  in  the  soil  is  retarded 
by  the  fineness  of  the  soil  particles,  in  the  same  way  that  the  down- 
ward movement  is  retarded.  Consequently,  drains  may  be  spaced 
farther  apart  in  sandy  soils  than  in  clay.  The  deeper  the  drains,  the 
farther  apart  the  lines  may  be  placed.  Figure  7  illustrates  the  rela- 
tion of  spacing  to  depth.  In  soils  ranging  from  sand  to  sandy  loam, 
drain  lines  may  be  placed  from  150  to  300  feet  apart ;  while  in  heavy 
silts  and  clays,  it  may  be  necessary  to  place  the  lines  as  close  together 
as  thirty  or  forty  feet.      It  is  not  possible  to  give  specific  rules  for 


-  -.■/ 


Fig.  6. — Correct  and  incorrect  grading  for  tile. 


either  the  depth  of  tile  or  the  spacing  between  lines,  even  for  similar 
types  of  soil.  Conditions  may  be  such  that  one  line  of  tile  will  be 
sufficient  to  drain  a  heavy  soil  while  several  lines  will  be  required  to 
drain  a  sandy  loam.  The  intercepting  system  illustrated  in  figure  2 
is  an  example  of  a  single  line  of  tile  reclaiming  a  considerable  area. 
Every  drainage  problem  calls  for  the  exercise  of  good  judgment  rather 
than  the  use  of  set  rules.  A  knowledge  of  both  surface  and  subsoil 
conditions  is  even  of  more  importance  in  designing  tile  drains  than 
in  designing  open  drains.  For  example,  a  soil  which  is  apparently 
a  clay  on  the  surface  may  be  quite  sandy  at  three  or  four  feet  below, 
or  the  reverse  may  be  the  case.  A  knowledge  of  these  conditions  is 
essential  to  the  proper  design  of  a  drainage  system. 

Table  I  shows  the  number  of  feet  of  tile  required  per  acre  when 
spaced  the  given  distances  apart.  To  these  figures  would  have  to 
be  added  whatever  mains  are  necessary  to  afford  an  outlet. 


13 


TABLE 

I 

Tile  Required 

to  Drain 

AN 

Acre  of 

Land 

Spacing, 
feet 

Tile  required 
per  acre, 
feet 

Spacing, 
feet 

Tile  required 
per  acre, 
feet 

30 

1452 

150 

291 

40 

1089 

200 

218 

50 

872 

300 

146 

75 

581 

400 

109 

100 

436 

Size  of  Tile: 

The  proper  size  of  tile  to  use  is  one  of  those  details  for  which  it 
is  difficult  to  give  definite  directions  because  of  the  many  influencing 
factors.  Farmers'  Bulletin  No.  187,  U.  S.  Department  of  Agricul- 
ture, gives  the  following  summary  of  the  conditions  which  determine 
the  size  of  drains,  particularly  the  mains. 


The  relation  of  spacing  to  depth. 


(1)  What  depth  of  water  per  acre  will  it  be  necessary  to  remove  from  the 
land  in  a  given  time,  say  twenty-four  hours,  in  order  to  secure  the  desired  con- 
dition of  the  soil? 

(2)  How  rapidly  will  the  water  be  brought  to  the  main  drains? 

(3)  What  surface  drainage  does  the  tract  have  that  will  be  available  for 
carrying  unusual  rains? 

(4)  What  is  the  nature  of  the  soil  as  regards  its  drainage  properties,  that 
is,  is  it  open  or  retentive? 

(5)  What  are  the  grades  upon  which  the  tile  must  be  laid? 


The  amount  of  rainfall  over  the  state  varies,  as  previously  stated, 
from  more  than  fifty  inches  to  less  than  ten  inches.  Drainage,  how- 
ever, has  to  deal  with  the  extremes  of  rainfall  rather  than  with  the 
yearly  totals.  Rather  heavy  rains  during  certain  parts  of  the  year 
will  cause  very  little  run-off  as  the  water  is  nearly  all  absorbed  by 
the  soil.  On  the  other  hand,  a  rather  moderate  rainfall  following 
a  period  of  wet  weather,  during  which  the  soil  has  become  saturated, 


14. 

may  almost  entirely  run  off.  Under  extreme  conditions,  in  which  the 
collecting  or  lateral  system  of  drains  is  adequate  and  the  soil  open, 
mains  may  well  be  designed  to  carry  a  run-off  of  one  inch  in  depth 
from  the  tract  in  twenty-four  hours.  Under  ordinary  conditions, 
mains  capable  of  carrying  in  twenty-four  hours  a  run-off  of  one-half 
inch  in  depth  of  water  from  the  entire  tract  will  be  found  adequate. 


DISCHARGE  CURVES  for  Drain  Tile  Based 

Dn 

Kutter's  Formula('n\015) 

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RJ 

R'f 

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« 

ACRES 
DRAINED 

■Slope  m  Feet  per  /OO  Feet 

Fig.  8.— Curves  showing  capacities  of  drain  tile  at  various  slopes,  and  acres 
drained  at  different  rates  of  run-off. 


15 

When  computing  run-off,  the  area  contributing  water  to  the  badly- 
drained  tract  should  be  considered  rather  than  the  area  actually  to 
be  drained. 

It  is  never  advisable  to  use  tile  smaller  than  four  inches  in 
diameter,  even  for  short  laterals;  in  fact,  some  tile  factories  have 
discontinued  the  making  of  drain  tile  less  than  four  inches  in  diameter. 
Even  with  the  greatest  care  irregularities  in  the  grade  or  laying  of 
the  tile  are  sure  to  occur.  A  slight  irregularity  in  a  line  of  small 
tile  has  a  much  more  serious  effect  on  its  efficiency  than  does  a  similar 
irregularity  in  a  line  of  larger  tile. 

Four-  and  six-inch  tile  (preferably  six-inch)  may  ordinarily  be 
used  for  lateral  drains  1500  feet  or  less  in  length.  Six-  and  eight- 
inch  tile  may  be  used  for  submains  and  the  upper  ends  of  mains. 
Some  factories  make  the  intermediate  sizes,  five-  and  seven-inch,  which 
can  of  course  be  used  in  their  proper  places.  From  the  diagram  in 
figure  8  the  carrying  capacities  of  tile  on  different  grades  can  be 
determined.  The  diagram  also  shows  the  number  of  acres  drained 
at  different  rates  of  run-off. 

Where  a  complete  system  is  installed  it  is  not  necessary  to  make 
the  capacity  of  the  main  drain  equal  to  the  combined  capacities  of 
the  laterals.  Lateral  drains  are  seldom  required  to  carry  their  full 
capacity;  in  fact,  a  drain  that  runs  full  for  a  considerable  time  may 
safely  be  considered  too  small. 

The  difference  between  the  cost  of  a  drainage  system  using  four- 
inch  tile  and  of  one  using  six-inch  tile  for  laterals,  lies  almost  entirely 
in  the  cost  of  the  tile  itself,  which  is  seldom  more  than  30  or  35  per 
cent  of  the  entire  cost  of  the  system.  The  smallest  trench  that  it  is 
practicable  to  dig  by  the  methods  usually  employed  in  California  will 
be  large  enough  for  six  or  even  eight-inch  tile.  There  is  not  enough 
difference  in  weight  between  a  four-inch  and  a  six-inch  tile  to  add 
materially  to  the  cost  of  laying,  and  the  cost  of  backfilling  will  be  the 
same  in  both  cases.  Furthermore,  incidental  expenses  do  not  increase 
in  direct  proportion  to  the  size  of  tile  used.  To  be  of  the  highest 
efficiency,  the  tile  must  be  of  sufficient  size  to  remove  all  surplus 
water  before  the  crops  are  injured,  even  after  the  heaviest  rainfall 
in  a  continued  wet  period. 

KINDS  OF  TILE 

Two  kinds  of  drain  tile  are  available  in  the  market,   clay  and 

cement.      Clay  drain  tile  are  made  in  sizes  varying  from  four  inches 

to  twenty-four  or  thirty  inches  in  diameter.      The  usual  practice  is 

to  increase  the  diameter  for  each  succeeding  size  by  two  inches  up  to 


16 

a  diameter  of  sixteen  inches,  and  by  four  inches  thereafter.  Some 
factories,  however,  make  tile  five,  seven,  and  fifteen  inches  in  diameter. 
Clay  tile  up  to  and  including  twelve  inches  in  diameter  are  usually 
made  in  one-foot  lengths,  and  in  two-foot  lengths  for  the  larger  sizes. 

The  tile  should  be  straight,  well-burned,  and  free  from  cracks  or 
other  defects.  The  use  of  so-called  "soft"  or  "porous"  tile  should 
be  discouraged.  From  a  practical  standpoint  tile  are  not  porous, 
and  a  "soft"  clay  tile  is  merely  the  result  of  under-burning  and 
should  be  looked  upon  as  defective.  It  is  sufficient  to  say,  in  this 
connection,  that  water  enters  a  tile  line  through  the  spaces  between 
the  individual  tile  and  not  by  passing  through  the  walls  of  the  tile 
themselves.  It  is  not  essential  that  tile  be  vitrified  or  "salt-glazed," 
although  a  vitrified  condition  is  by  no  means  undesirable.  Salt- 
glazed,  fully-vitrified  sewer  pipe  is  frequently  used  instead  of  the 
regular  drain  tile;  in  this  case,  however,  the  joints  are  left  un- 
cemented.  The  use  of  sewer  pipe  is  objectionable  only  in  that  it 
usually  requires  a  little  more  time  in  laying,  and  the  extra  weight 
caused  by  the  unnecessary  "bell"  adds  somewhat  to  the  freight  costs. 
The  cost  of  first-grade  sewer  pipe  is  usually  prohibitive  so  far  as 
drainage. work  is  concerned,  but  "seconds"  can  often  be  purchased 
at  prices  comparable  to  those  of  drain  tile.  Sewer  seconds  should  be 
rather  closely  inspected  before  being  used,  and  inferior  tile  discarded. 

Cement  tile  may  still  be  considered  to  be  in  the  experimental  stage. 
Satisfactory  cement  tile  under  twelve  inches  in  diameter  can  not  be 
made  as  cheaply  as  can  clay  tile,  but  over  that  size  the  cost  of  the 
former  is  somewhat  less.  One  part  of  Portland  cement  and  two  or 
three  parts  of  clean  sand,  properly  mixed  and  cured,  make  a  satis- 
factory product.  Cement  tile  made  of  the  same  constituents  will  vary 
considerably  if  made  by  different  persons.  The  average  tile  user  is 
better  able  to  judge  the  quality  of  clay  tile  than  he  is  of  cement  tile 
as  they  are  found  in  the  yard  or  at  the  local  dealers.  Home-made 
cement  tile  are  usually  of  inferior  quality  unless  experienced  work- 
men are  employed. 

CONSTRUCTION  OF  TILE  DRAINS 
Laying  out  the  Drain: 

When  laying  out  a  drain,  stakes  one  foot  or  more  in  length  should 
be  placed  by  the  engineer  at  intervals  of  fifty  or  one  hundred  feet 
along  the  line  and  plainly  marked  with  a  station  number  indicating 
the  distance  from  the  outlet  or  beginning  of  that  particular  drain. 
Thus,  stakes  marked  1  +  00,  1  +  25,  or  2  -f-  50,  indicate  that  there 
are  respectively  100,  125,  or  250  feet  of  drain  up  to  these  points. 


17 

Close  to  each  of  these  stakes  the  engineer  should  drive  another,  the 
top  of  which  is  flush  with  the  ground  surface,  on  which  he  takes  his 
levels.  It  is  from  this  latter  stake,  generally  called  the  ' '  grade  stake, ' ' 
that  he  measures  the  ' '  cut ' '  or  depth  at  that  point.  The  grade  stakes 
are  so  placed  as  to  be  reasonably  safe  and  must  not  be  disturbed  by 
the  digger.      The  depth  of  the  trench  at  this  point  is  either  marked 


Fig.  9. — Trench  kept  straight  by  means  of  cord. 

on  the  guard  stake  or  furnished  the  workmen,  the  latter  method  being 
preferable  as  the  guard  stakes  are  liable  to  be  broken  down  and 
lost.  Before  commencing  the  excavation,  the  workmen  should  stretch 
a  line  about  six  inches  to  one  side  of  the  line  of  stakes  as  shown  in 
figure  9;  digging  to  this  line  will  insure  a  clean,  straight  cut. 


Ditching  Tools  and  Machinery: 

Although  there  are  several  hand  implements  for  constructing  tile 
drains,  such  as  the  short-handled  tile  spade  and  tile  fork,  grading 


18 

scoops  of  various  sizes,  and  tile  hooks,  the  only  tools  in  common  use 
in  California  are  the  pick  and  long-handled  shovel.  Figure  10  shows 
several  tools  which  will  probably  become  more  common  in  California 
as  drainage  work  develops.  The  grading  scoop  especially  should  be 
more  generally  used. 

There  are  several  types  of  machinery  for  use  in  excavating  trenches 
for  tile  drains.  These  vary  from  the  plow  which  costs  less  than  $20 
and  is  suitable  for  loosening  the  surface  foot  of  the  trench,  to  the 
power-driven  trenching  machine,  costing  from  $1500  to  $6000,  that 
will  excavate  a  trench  into  which  the  tile  can  be  placed  without  further 


Fig.  10. — Tools  used  in  constructing  tile  drains. 


work.  Figure  11  shows  an  excavator  at  work  digging  a  trench  for 
tile  drains.  The  purchase  of  an  expensive,  power-driven  machine  is 
not  advisable  unless  there  are  ten  or  fifteen  miles  of  tile  to  be  laid,  or 
unless  the  machine  can  be  rented  to  others  who  contemplate  tile  drain- 
age. A  good  trenching  machine  must  be  able  to  operate  in  any  soil 
that  is  free  from  rock;  it  must  be  capable  of  cutting  true  to  grade, 
and  it  must  be  strongly  and  simply  constructed.  It  is  often  possible 
to  borrow  trenching  machinery  that  is  temporarily  idle,  from  a  town 
where  it  has  been  used  in  sewer  construction.  One  of  the  principal 
advantages  of  excavating  with  machinery  is  in  having  the  work  done 
quickly.  Under  favorable  conditions  it  is  not  unusual  for  a  trencher 
to  dig  one-quarter  to  one-half  mile  of  four-foot  trench  per  day.     In 


19 

determining  the  cost  of  trenching  by  machinery,  the  items  of  oper- 
ation, repairs,  and  depreciation  should  all  be  included. 

Digging  to  Grade: 

Digging  to  true  grade  is  the  important  operation  in  excavating 
for  a  drain.  Several  methods  are  in  use  by  which  the  bottom  can  be 
graded  from  the  grade  stakes  set  by  the  engineer.  If  the  workmen 
are  not  familiar  with  one  of  these,  the  engineer  should  instruct  them. 
A  very  simple  method,  and  one  which  gives  the  true  grade  at  all 
points  along  the  line,  is  to  stretch  a  light,  stout  cord  on  cross-bars 
directly  over  the  trench,  and  say  5%  feet  above  the  proposed  bottom. 
By  measuring  from  this  cord  with  a  5!/2-foot  pole,  the  grade  of  the 


Fig.  11. — Drainage  excavator  digging  trench  for  tile  drain. 


bottom  at  any  point  is  easily  determined.  The  line  is  placed  just 
high  enough  to  make  the  "cut"  below  the  grade  stake,  plus  the  dis- 
tance of  the  line  above  the  grade  stake,  equal  to  5%  feet.  Thus,  if 
the  cut  at  station  5  -f-  00  is  given  as  4.0  feet,  and  that  at  station 
6  4-  00  is  given  as  3.5  feet,  the  cross-bar  must  be  1.5  feet  above  the 
grade  stake  at  station  5  +  00,  and  2.0  feet  above  the  grade  stake  at 
station  6  +  00.  In  placing  the  cross-bar  which  supports  the  cord, 
one  stake  supporting  the  cross-bar  is  driven  down  alongside  the  grade 
stake  until  the  cross-bar  is  the  required  distance  above  the  stake ;  then 
another  stake  is  driven  on  the  opposite  side  of  the  trench  until  a  car- 
penter's level  shows  the  cross-bar  to  be  level.  If  the  grade  stakes  are 
100  feet  apart  it  is  well  to  support  the  cord  at  one  or  more  points 
between  so  that  there  shall  be  no  sag.      This  can  be  done  quite  accu- 


20 

rately  by  sighting  along  the  cord.  A  measuring  pole  of  other  length 
than  5%  feet  may  be  used,  but  the  height  of  the  cord  above  the  grade 
stakes  must  then  be  changed  accordingly.  Figure  12  shows  the 
method  of  securing  the  correct  grade  by  means  of  an  overhead  cord. 
The  cord  should  be  retightened  frequently  as  changes  in  temperature 
and  moisture  conditions  cause  it  to  sag,  and  it  should  always  be  re- 
tightened  after  having  remained  on  the  cross-bars  over  night. 


Fig.  12. — Grading  the  trench  by  means  of  overhead  cord. 


Engineers  usually  furnish  figures  showing  cuts  and  other  meas- 
urements in  feet  and  decimals  of  a  foot,  and  not  in  inches.  Workmen 
unfamiliar  with  this  method  of  measuring  should  be  furnished  with 
measuring  rods  properly  graduated;  or,  if  this  for  any  reason  is  not 
feasible,  the  engineer  should  change  his  figures  to  the  form  better 
understood  by  the  layman.  Table  II  gives  the  decimals  of  a  foot 
converted  to  inches. 


21 


TABLE  II 

Decimals  of  a  Foot  to  Inches 

Ft.         In.  Ft.         In.  Ft.         In.  Ft.         In.  Ft.  In. 

.20  =  23/8  .40  =  4%  .60  =  7%  .80=    9% 

.01=    %  .21  =  2%  .41  =  4%  .61  =  7%  .81=    9% 

.02=    %  .22  =  2%  .42  =  5  .62=7%  .82=    9% 

.03=    %  .23  =  2%  .43  =  5%  .63  =  7%  .83  =  10 

.04=    %  .24  =  2%  .44  =  5%  .64  =  7%  .84  =  10% 

.05=    %  .25  =  3  .45  =  5%  .65  =  7%  .85  =  10% 

.06=    %  .26  =  3%  .46  =  51/2  .66  =  7%  .86  =  10% 

.07=    %  .27  =  3%  .47  =  5%  .67  =  8  .87  =  10% 

.08  =  1  .28  =  3%  .48  =  5%  .68  =  8%  .88  =  10% 

.09  =  1%  .29  =  3%  .49  =  5%  .69  =  8%  .89  =  10% 

.10  =  1%  .30  =  3%  .50  =  6  .70  =  8%  .90  =  10% 

.11  =  1%  .31  =  3%  .51  =  6%  .71  =  8%  .91  =  10% 

.12  =  1%  .32  =  3%  .52  =  6%  .72  =  8%  .92  =  11 

.13  =  1%  .33  =  4  .53  =  6%  .73  =  8%  .93  =  11% 

.14  =  1%  .34  =  4%  .54  =  6%  .74  =  8%  .94  =  11% 

.15  =  1%  .35  =  4%  .55  =  6%  .75  =  9  .95  =  11% 

.16  =  1%  .36  =  4%  .56  =  6%  .76  =  9%  .96  =  11% 

.17  =  2  .37  =  4%  .57  =  6%  .77  =  9%  .97  =  11% 

.18  =  2%  .38  =  4%  .58  =  7  .78  =  9%  .98  =  11% 

.19  =  2%  .39  =  4%  .59  =  7%  .79  =  9%  .99  =  11% 


Laying  Tile: 

The  digging  of  the  trench  and  the  laying  of  the  tile  should  always 
begin  at  the  outlet  and  proceed  toward  the  upper  end.  Figure  13 
shows  the  tile  so  distributed  in  the  field  that  it  can  be  laid  with  the 
least  handling.  It  is  generally  best  to  lay  the  tile  as  soon  as  the 
trench  is  ready  in  order  to  avoid  possible  damage  to  the  trench  by 
rains,  caving  banks,  etc.  If  the  bottom  of  the  trench  is  known  to 
be  true  to  grade  at  every  point,  the  smaller  sizes  of  tile  can  be  laid 
from  the  bank  with  a  tile  hook  (see  fig.  10)  ;  otherwise  they  are  laid 
by  a  man  who  stands  in  the  trench  and  places  each  tile  after  having 
made  the  bottom  true  to  grade  with  a  grading  scoop  or  shovel.  The 
tiles  are  laid  end  to  end  as  closely  as  they  will  lie  in  the  trench.  Tiles 
will  often  be  found  whose  ends  are  not  square,  but  by  turning  them 
slightly  they  can  be  made  to  fit  quite  closely.  Figure  14  shows  how 
tiles  with  such  ends  can  sometimes  be  matched  so  as  to  make  a  good 
joint.  A  tile  with  a  small  chip  broken  from  the  end  but  which  is 
otherwise  sound  can  be  used  by  placing  the  broken  side  down  or  by 
carefully  covering  the  break  with  a  piece  of  broken  tile  or  a  flat  stone. 
A  tile  that  is  cracked  more  than  one-quarter  of  its  length,  or  is  broken 
on  the  end  so  that  the  break  can  not  be  properly  covered,  should  be 
discarded.      It  should  be  remembered  that  a  tile  which  fails  after 


22 

being  placed  in  the  ground  will  completely  destroy  the  usefulness  of 
the  entire  line  above  it;  it  is  obviously  poor  economy  to  endanger  the 
efficiency  of  an  entire  line  in  order  to  save  a  joint  of  tile. 

Just  as  soon  as  a  tile  is  in  its  proper  place,  a  little  earth  should  be 
cut  from  the  side  of  the  trench  and  placed  about  the  tile  so  as  to  pre- 
vent it  from  rolling  out  of  line.  After  50  or  100  feet  of  tile  are  laid, 
and  at  the  end  of  each  clay's  work,  the  tile  laid  should  be  covered 


SE^S^ailfr 

r~                                                                                                                                  \  - 

■.•■.;':3il^OT 

Fig.   13. — Trench  ready  and  tile  properly  distributed. 

with  earth  to  a  depth  of  three  or  four  inches  so  as  to  prevent  possible 
dislocation  or  injury  to  the  tile  from  stones  or  chunks  of  earth  which 
might  fall  upon  them.  There  need  be  no  fear  ordinarily  that  the  tile 
will  be  laid  so  close  together  that  the  water  can  not  enter.  The  former 
practice  of  covering  the  joints  with  straw  or  gravel  to  prevent  the 
entrance  of  soil  is  now  largely  abandoned  as  being  unnecessary  and 
expensive.  Well-laid  tiles  will  be  close  enough  together  to  prevent  the 
entrance  of  any  foreign  matter  and  will  yet  admit  water  freely.    The 


23 

use  of  rock  or  gravel  in  covering  a  tile  line  is  not  objectionable,  but 
the  use  of  brush  or  sticks  should  be  discouraged. 
Backfilling : 

If  the  tile  are  to  be  inspected  by  the  engineer  such  inspection 
should  be  done  just  before  it  is  covered.  The  filling  of  the  trench 
can  be  accomplished  in  several  ways.  In  places  where  the  work  is 
crowded,  such  as  in  an  orchard  or  around  buildings,  the  backfilling 
can  best  be  done  by  hand  with  shovels.  In  the  open  field  the  soil  is 
usually  plowed  into  the  trench.  A  long  doubletree  is  provided  so 
that  one  horse  or  one  team  is  on  each  side  of  the  trench.  This  method 
requires  from  two  to  three  men  and  steady  teams.  Small  slip  scrapers 
or  four-horse  "fresnos"  are  sometimes  used,  in  which  case  the  team 
works  on  the  opposite  side  of  the  trench  from  the  scraper. 

All  of  the  earth  excavated  from  the  trench  should  be  replaced; 
otherwise  there  will  be  a  depression  along  the  line  when  the  soil 
settles. 


Fig.  14. — Tiles  whose  ends  are  not  square  may  be  rotated  to  make  a  good  joint. 


BOX  DRAINS 

Box  drains  may  be  used  when  lumber  can  be  secured  at  a  reason- 
able price  and  tile  is  very  expensive.  The  installation  of  box  drains 
is  similar  in  every  respect  to  that  of  tile  and  the  same  care  should  be 
used.  Redwood  lumber  is  relatively  durable  for  underground  work 
and  in  California  should  be  used  in  preference  to  pine  or  fir.  It  is 
reasonable  to  expect  boxes  to  last  for  ten  or  twelve  years ;  if  kept  wet 
during  the  entire  year  they  will  last  much  longer. 

A  simple  form  of  box  is  shown  in  figure  15a.  The  lumber  for  the 
smaller  boxes  should  run  lengthwise,  and  where  conditions  will  permit 
the  sections  may  be  from  twelve  to  sixteen  feet  long.  The  top  is  nailed 
tightly  to  the  sides,  but  the  bottom  is  held  away  from  the  sides  by 
short  pieces  of  lath  placed  at  intervals  of  three  or  four  feet.  In  boxes 
where  the  interior  dimensions  are  greater  than  eight  inches  square, 
two-inch  lumber  should  be  used  and  the  top  and  bottom  put  on  cross- 


24 


wise  as  shown  in  figure  15&.  In  large  boxes  for  main  drain,  the  lum- 
ber for  the  top,  bottom,  and  sides  should  all  run  crosswise  (figure 
15c).  The  bottom  pieces  should  be  separated  so  that  when  the  lumber 
becomes  wet  it  will  not  swell  and  close  all  openings  for  the  water. 
The  use  of  box  drains  without  bottoms  is  not  advisable  as  the  water 
is  likely  to  undermine  the  sides  and  cause  the  box  to  settle.  Further- 
more, the  roughness  of  the  ground  reduces  the  capacity  of  the  drain. 

b  c 


X 

s 

s 

s 

Fig.  15. — Types  of  lumber  box  drains. 

SUKFACE  INLETS,  SILT  BOXES,  AND  OUTLETS 
Surface  water  should  not  be  allowed  to  enter  directly  into  a  tile 
line  unless  some  provision  is  made  to  exclude  sand,  dirt,  sticks,  and 
other  rubbish.  Figures  16  and  17  show  two  methods  of  screening 
surface  water  before  it  enters  a  tile  line.  If  there  is  a  considerable 
quantity  of  water  the  stone  filter,  illustrated  in  figure  16,  should 
extend  over  a  greater  length  of  tile  than  shown.     The  types  of  screen 


Fig.  16. — Buried  stone  filter  for  admitting  surface  water  to  a  tile  line. 

shown  in  figure  17  admit  water  more  readily  to  the  tile  line,  but  when 
located  in  open  fields  are  somewhat  of  an  obstruction  to  cultivation. 

It  is  good  practice  to  install  silt  boxes  at  intervals  along  a  tile 
drain  to  catch  and  retain  any  silt  that  may  enter  the  line.  These 
boxes  may  be  made  of  lumber,  concrete,  or  brick.  A  very  satisfactory 
lumber  silt-box  which  combines  also  manhole  and  observation  well  is 
shown  in  figure  18.  It  is  inadvisable  to  construct  silt  boxes  so  small 
that  tliey  can  not  be  readily  entered  and  cleaned.      They  should  be 


25 

placed  at  points  where  the  grade  changes  to  a  flatter  one,  or  where 
there  are  abrupt  changes  in  direction  of  the  line.  The  junction  of 
two  lines  is  easily  effected  through  such  a  box  although  in  a  "regular*' 
system  of  drains  it  would  not  be  advisable  to  place  a  box  at  each 
junction. 

The  outlet  of  a  tile  drainage  system,  unless  very  favorably  located 
should  be  protected  by  some  device  which  will  prevent  the  tile  from 
washing  out  or  becoming  injured  or  displaced.  The  outlet  protection 
may  be  made  of  lumber,  stone,  brick,  or  concrete,  the  design  depending 
upon  the  conditions  which  exist  at  the  outlet.      In  any  case  care 


Fig:.  17. — Surface  inlets  with  screens. 


should  be  taken  to  secure  a  good  foundation  and  anchorage  so  that  the 
structure  will  not  be  undermined.  Figure  19  shows  an  outlet  protec- 
tion for  small  tile,  and  figure  20  illustrates  one  suitable  for  larger  tile. 
Whatever  construction  material  is  used  in  making  silt  wells  may  also 
be  used  for  outlet  protections. 


MAINTENANCE  OF  TILE  DKAINS 
Tile  drains  which  are  properly  laid  will  require  very  little  main- 
tenance. The  silt  boxes  should  be  inspected  frequently  during  the 
first  year  and  at  regular  intervals  thereafter,  and  should  be  kept  free 
from  silt.  The  covers  of  silt  boxes  should  be  kept  closed  at  all  times ; 
if  necessary  they  should  be  locked  so  that  they  can  not  be  opened  by 
inquisitive  persons.  Tumble  weeds,  rabbits,  and  squirrels  may  enter 
the  silt  boxes  and  obstruct  the  tile  lines  unless  this  precaution  is 
observed. 


26 

Soil  will  not  seal  the  joints  and  prevent  the  entrance  of  water  into 
the  tile  lines  unless  very  unusual  conditions  prevail.  There  need  be 
no  fear  of  the  roots  of  fruit  trees  growing  into  a  tile  line  unless  the 
tile  carries  water  when  the  surrounding  soil  is  dry.  Such  a  condition 
would  exist  when  the  drain  taps  a  spring  which  flows  long  after  the 
surrounding  area  has  become   dry.      Cottonwood  and  willow   trees 


Bo/f^ 


■2'*6*3"-3'- 


.^ 


2"' 6" 


Fig.  18. — Combination  manhole  and  silt  box  with  cover, 


should  not  be  allowed  to  grow  within  fifty  feet  of  a  tile  line  as  there 
is  more  danger  from  these  water-loving  trees  than  from  fruit  trees. 
Should  a  tile  line  become  obstructed  in  any  way,  silt  boxes  located 
at  frequent  intervals  will  aid  materially  in  locating  the  obstruction. 
A  number  of  devices  have  been  developed  for  cleaning  sewers  which 
can  be  used  for  drain  tile  when  necessary.    These  may  also  be  found 


27 

useful  during  construction,  especially  if  the  tile  is  laid  in  a  wet, 
muddy  trench.  The  most  common  form  of  tile  cleaner  is  one  whose 
several  sections  can  be  joined  together  when  the  rods  are  held  at  right 
angles  but  can  not  be  unhooked  when  extended.      These  rods  may 


be  used  with  or  without  any  of  the  various  attachments  such  as  an 
auger,  wire  brush,  hoe,  or  spiral  cutter.  A  very  simple  brush  can 
be  made  by  wrapping  a  piece  of  leather  belting  around  a  cylindrical 


Fig.  20. — Stone  or  brick  outlet  protection. 


rod,  the  belting  first  having  been  driven  full  of  wire  nails  of  such  a 
length  that  the  completed  brush  will  not  quite  fill  the  tile.  Figure  21 
shows  a  cleaning  device  of  this  type.  Care  must  be  exercised  not  to 
use  anything  that  may  become  detached  or  which  will  catch  on  the 
tile.  Two  hundred  and  fifty  feet  or  more  of  rod  can  be  operated  in  a 
straight  tile  line. 


28 


COST  OF  TILE  DRAINAGE 

The  ultimate  question  with  regard  to  drainage  work  is,  will  it 
pay?  In  order  to  determine  this  one  must  know  what  it  will  cost. 
From  what  has  been  said  regarding  the  varying  sizes  of  tile,  spacing 
and  depth  of  drains,  and  the  various  structures  required,  it  is  evident 
that  definite  statements  on  the  question  of  cost  can  be  made  only  when 
the  complete  details  for  a  particular  project  are  at  hand. 

Tile  are  sold  by  the  foot,  with  discounts  from  the  list  price  on 
orders  of  1000  feet  or  more,  and  further  discounts  for  carload  lots. 
Prices  for  tile  are  much  higher  in  California  and  the  other  western 
states  than  in  the  east  or  middle  west.  There  are  probably  less  than 
a  half-dozen  factories  on  the  Pacific  Coast  which  manufacture  clay 
drain-tile  exclusively,  most  factories  making  drain-tile  to  order  or  as 


Fig.  21. — Sewer  rods  and  tile  cleaning  devices. 

a  side  line  in  the  manufacture  of  other  clay  products.  Table  III  con- 
tains quotations  and  weights  per  foot  as  furnished  by  one  of  the 
California  factories  which  makes  drain  tile  exclusively. 

TABLE  III 

Costs  and  Weights  of  Clay  Drain  Tile 


ize 
in. 

Cost  per  1000  ft.* 

Weight 
lbs. 

per 

ft. 

Size 
in. 

Cost 

per  1000  ft.* 

Weight  per  ft 
lbs. 

4 

$40 

8 

10 

$110 

27 

5 

50 

10 

12 

160 

40 

6 

60 

14 

14 

200 

44 

8 

80 

21 

16 

250 

55 

*  F.o.b.  factory  in  carload  lots,  minimum  car  26,000  lbs.;  10  per  cent  discount 
for  cash. 


Factories  which  make  drain  tile  to  order  or  as  a  side-line  quote 
higher  prices,  while  at  least  one  factory  making  drain  tile  exclusively 
quotes  lower  prices  than  those  given.      To  the  final  cost  of  tile  must 


29 

be  added  the  freight  charges  and  the  cost  of  hauling  from  the  railroad 
to  the  field. 

The  excavation  by  hand  of  trenches  for  drain  tile  will  cost  from 
5  to  10  cents  per  linear  foot  for  depths  of  three  to  five  feet.  The  cost 
varies  somewhat  with  the  season,  the  soil,  and  the  amount  of  labor 
available.  Labor  can  usually  be  secured  for  this  kind  of  work  for 
25  cents  per  hour.  Laying  and  blinding  will  cost  from  one-quarter 
to  one-half  cents  per  lineal  foot,  and  backfilling  from  one  to  two  cents 
per  linear  foot. 

The  total  cost  of  installing  four-inch  tile  drains  at  a  depth  of  3y2 
feet,  when  all  the  work  is  done  by  hand,  may  vary  from  11  to  18  cents 
per  linear  foot.  The  use  of  six-  and  eight-inch  tile  does  not  materially 
increase  the  cost  of  excavation,  laying,  and  backfilling.  Machine-dug 
trenches  should  lower  the  cost  of  excavation  to  from  one  and  one-half 
to  four  cents  per  linear  foot,  while  experienced  labor  and  the  use  of 
improved  tiling  tools  may  eventually  make  excavation  by  hand  cheaper 
than  the  prices  given  above. 

These  statements  regarding  the  cost  of  tile  drainage  should  be 
used  only  as  a  general  guide  in  making  estimates.  Short  drains 
which  follow  the  natural  system  may  often  be  installed  by  the  farmer 
without  a  great  deal  of  expense  beyond  the  cost  of  the  tile  and  that 
of  the  labor  which  he  usually  hires.  Extensive  systems  are  generally 
installed  by  contractors  who  are  equipped  for  and  familiar  with 
handling  this  kind  of  work.  Contractors  can  usually  continue  work 
without  interruption,  whereas  the  farmer  may  find  it  necessary  to 
temporarily  discontinue  the  work  at  a  critical  point  because  of  his 
other  farm  duties. 

VERTICAL   DRAINAGE 

By  vertical  drainage  is  meant  the  passing  of  drainage  water 
vertically  through  the  soil  into  a  porous  bed  of  sand  or  gravel  beneath ; 
it  is  effected  by  means  of  wells  or  pipes  extending  into  the  porous 
substratum.  Whether  or  not  drainage  can  be  accomplished  in  this 
way  depends  entirely  upon  local  conditions  and  this  method  is  by 
no  means  generally  applicable. 

Ideal  conditions  for  vertical  drainage  would  be  presented  by  a 
surface  soil  which  is  kept  wet  by  the  accumulation  of  water  above 
an  impervious  layer  of  clay  or  hardpan,  beneath  which  is  a  layer  of 
sand  or  gravel,  the  latter  containing  no  water  or  permitting  the  water 
to  escape  readily.  Conditions  as  these  are  very  infrequent;  on  the 
contrary,  the  subsoil  is  more  often  filled  with  water  which  does  not 
flow  away.      It  would  be  useless  to  attempt  vertical  drainage  where 


30 

there  is  no  porous  layer  below,  even  though  the  subsoil  were  dry, 
as  the  capacity  of  the  latter  for  water  would  be  very  limited  and  the 
drain  would  soon  become  inoperative.  It  would  also  be  useless  to 
attempt  vertical  drainage  where  the  ground  water  is  within  a  few 
feet  of  the  surface  during  the  time  when  surface  drainage  is  most 
necessary. 

Vertical  drainage,  where  practicable,  may  be  accomplished  by 
boring  an  eight-  or  ten-inch  hole  well  into  the  porous  stratum  and 
lining  this  hole  with  ordinary  drain  tiles  set  one  on  top  of  another. 
The  top  must  be  securely  covered  and  screened  so  as  to  prevent  the 
entrance  of  silt  or  trash  into  the  drain.  Another  method  of  accom- 
plishing vertical  drainage  is  to  break  up  the  impervious  stratum  with 
dynamite.  This  method  is  more  applicable  where  the  impervious 
layer  is  hardpan  than  where  it  is  clay.  The  clay  would  have  a 
tendency  to  soon  puddle  back  into  an  impervious  layer,  and  instead 
of  breaking  and  shattering  would  pack  and  burn  at  the  point  of  the 
explosion.3 

Every  instance  of  contemplated  vertical  drainage  should  be  thor- 
oughly examined,  as  more  often  than  otherwise  subsoil  conditions  will 
be  found  unsuited  to  this  type  of  drainage. 

CO-OPERATION    IN    DRAINAGE 

It  is  seldom  that  a  farmer  can  install  an  extended  and  compre- 
hensive drainage  system  without  co-operating  to  some  extent  with 
other  landowners.  Most  frequently  when  co-operation  is  necessary  it 
is  in  securing  an  outlet.  The  right  to  drain  one's  land  should  not  be 
abridged  by  the  prejudices  of  his  neighbor,  especially  when  there 
would  be  no  injury  to  the  neighbor;  but  the  rights  of  those  owning 
lower  land  which  must  be  crossed  by  the  drains  of  another  must  not 
be  ignored,  and  if  any  injury  whatever  is  sustained  it  should  be  paid 
for.  As  a  matter  of  fact,  it  more  frequently  occurs  that  a  drain 
benefits  the  lower  land  by  crossing  it,  and  some  arrangement  should 
therefore  be  made  whereby  the  cost  of  such  a  drain  is  borne  by  both 
parties.  So  many  questions  are  involved  in  such  circumstances  that 
it  is  impossible  to  arrive  at  any  conclusions  without  a  knowledge  of 
all  of  the  facts  pertaining  to  the  individual  case.  These  matters, 
however,  should  be  amicably  settled  before  work  is  begun. 

It  is  frequently  desirable  for  three  or  four  farms  to  join  in  one 
system  of  drains  having  a  single  outlet.  Such  a  system  may  be  in- 
stalled as  if  the  entire  tract  belonged  to  one  man,  and  can  be  con- 


3  Bulletin  209,  Kansas  State  Agricultural  College. 


31 

structed  without  reference  to  line  fences.  Agreements  for  co-operation 
may  be  either  oral  or  written;  in  either  case  thorough  co-operation  is 
desirable.  The  cost  of  the  completed  system  should  be  apportioned 
with  respect  to  the  relative  acreage  drained  on  the  individual  farms, 
rather  than  with  regard  to  the  costs  of  the  drains  on  the  different 
farms.  C,  whose  farm  lies  higher  than  those  of  his  neighbors,  should 
help  pay  for  the  increased  size  of  the  outlet  drain  through  A  and  B 
made  necessary  by  C  's  drainage,  while  A  and  B  are  both  benefited  by 
the  drainage  of  the  tracts  above  them. 

The  adjustment  of  the  cost  of  cooperative  drainage  is  a  delicate 
matter  and  the  difficulties  increase  with  the  number  of  co-operative 
parties.  Nevertheless,  co-operative  drainage  should  be  encouraged  as 
it  usually  results  in  more  thorough  and  cheaper  drainage  for  all  con- 
cerned than  would  otherwise  be  possible. 


STATION  PUBLICATIONS   AVAILABLE   FOR  FREE   DISTRIBUTION 


REPORTS 

1897.     Resistant  Vines,  their  Selection,  Adaptation,   and  Grafting.     Appendix  to  Viticultural 
Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment   Station  for   1898-1901. 

1903.  Report  of  the  Agricultural  Experiment   Station  for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment   Station  for   1903-04. 

1914.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station,   July, 

1913-June,    1914. 

1915.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station,   July, 

1914-June,    1915. 

1916.  Report  of  the  College  of  Agriculture   and  the  Agricultural   Experiment   Station,   July, 

1915-June,   1916. 

BULLETINS 


No. 

230. 
241. 
242. 
244. 
246. 
248. 

249. 
250. 
251. 


252. 
253. 

255. 
257. 
261. 

262. 

263. 
264. 
265. 
266. 


No. 
108. 
113. 
114. 
115. 
117. 

118. 
121. 

124. 
126. 
127. 
128. 
129. 
130. 
131. 
132. 
133. 
134. 
135. 
136. 
137. 
138. 
139. 


140. 

141 
142 
143 

144 

145 


Enological  Investigations. 

Vine  Pruning  in  California,  Part  I. 

Humus  in  California  Soils. 

Utilization  of  Waste  Oranges. 

Vine  Pruning  in  California,  Part  II. 

The  Economic  Value  of  Pacific  Coast 

Kelps. 
Stock-Poisoning  Plants  of  California. 
The  Loquat. 
Utilization  of  the  Nitrogen  and  Organic 

Matter   in    Septic   and   Imhoff   Tank 

Sludges. 
Deterioration  of  Lumber. 
Irrigation   and   Soil   Conditions   in  the 

Sierra  Nevada  Foothills,  California. 
The   Citricola   Scale. 
New  Dosage  Tables. 
Melaxuma    of    the    Walnut,     "Juglans 

regia." 
Citrus   Diseases   of   Florida   and   Cuba 

Compared  with  Those  of  California. 
Size  Grade  for  Ripe  Olives. 
The  Calibration  of  the  Leakage  Meter. 
Cottonv  Rot  of  Lemons  in  California. 
A  Spotting  of  Citrus  Fruits  Due  to  the 

Action  of  Oil  Liberated  from  the  Rind. 


No. 

267.  Experiments  with  Stocks  for  Citrus. 

268.  Growing  and  Grafting  Olive  Seedlings. 

270.  A  Comparison  of  Annual  Cropping,  Bi- 

ennial Cropping,  and  Green  Manures 
on  the  Yield  of  Wheat. 

271.  Feeding  Dairy  Calves  in  California. 

272.  Commercial  Fertilizers. 

273.  Preliminary  Report  on  Kearney  Vine- 

yard Experimental  Drain. 

274.  The  Common  Honey  Bee  as  an  Agent 

in   Prune   Pollination. 

275.  The  Cultivation  of  Belladonna  in  Cali- 

fornia. 

276.  The  Pomegranate. 

277.  Sudan  Grass. 

278.  Grain   Sorghums. 

279.  Irrigation  of  Rice  in  California. 

280.  Irrigation  of  Alfalfa  in  the  Sacramento 

Valley. 

281.  Control  of  the  Pocket  Gophers  in  Cali- 

fornia. 

282.  Trials  with  California  Silage  Crops  for 

Dairy  Cows. 

283.  The  Olive  Insects  of  California. 

284.  Irrigation  of  Alfalfa  in  Imperial  Valley. 

285.  The  Milch  Goat  in  California. 


Grape  Juice. 

Correspondence  Courses  in  Agriculture. 

Increasing  the  Dutv  of  Water. 

Grafting  Vinifera  Vineyards. 

The  Selection  and  Cost  of  a  Small 
Pumping  Plant. 

The  County  Farm  Bureau. 

Some  Things  the  Prospective  Settler 
Should  Know. 

Alfalfa   Silage  for  Fattening  Steers. 

Spraying  for  the  Grape  Leaf  Hopper. 

House  Fumigation. 

Insecticide  Formulas. 

The  Control  of  Citrus  Insects. 

Cabbage  Growing  in   California. 

Spraying  for  Control  of  Walnut  Aphis. 

When  to  Vaccinate  against  Hog  Cholera. 

County  Farm  Adviser. 

Control  of  Raisin    Insects. 

Official  Tests  of  Dairy  Cows. 

Melilotns  Indica. 

Wood  Decay  in  Orchard  Trees. 

The  Silo  in  California  Agriculture. 

The  Generation  of  Hvdrocvanic  Acid 
Gas  in  Fumigation  by  Portable  Ma- 
chines. 

The  Practical  Application  of  Improved 
Methods  of  Fermentation  in  Califor- 
nia Wineries  during  1913  and  1914. 

Standard  Insecticides  and  Fungicides 
vorsns  Secrpf  Preparations. 

Practical  and  Inexpensive  Poultry  Ap- 
pliances. 

Control  of  Grasshoppers  in  Imperial 
Valley: 

Oidium  or  Powderv  Mildew  of  the  Vine. 

SucerestionH  to  Poultrvmen  concerning 
Chicken  Pox. 


CIRCULARS 
No. 
146. 


Jellies    and    Marmalades    from    Citrus 
Fruits. 

147.  Tomato   Growing  in  California. 

148.  "Lungworms." 

150.  Round  Worms  in  Poultry. 

151.  Feeding  and  Management  of  Hogs. 

152.  Some  Observations  on  the  Bulk  Hand- 

ling of  Grain  in  California. 

153.  Announcement  of  the  California   State 

Dairy  Cow  Competition,    1916—18. 

154.  Irrigation    Practice  in   Growing   Small 

Fruits   in  California. 

155.  Bovine  Tuberculosis. 

156.  How  to  Operate  an  Incubator. 

157.  Control  of  the  Pear  Scab. 

158.  Home  and  Farm  Canning. 

159.  Agriculture  in  the   Imperial  Valley. 

160.  Lettuce    Growing   in    California. 

161.  Potatoes  in   California. 

162.  White    Diarrhoea    and    Coccidiosis    of 

Chicks. 

163.  Fundamentals  Affecting  the  Food  Sup- 

ply of  the  United  States. 

164.  Small  Fruit  Culture  in  California. 

165.  Fundamentals    of    Sugar    Beet    under 

California  Conditions. 

166.  The  County  Farm  Bureau. 

167.  Feeding  Stuffs  of  Minor  Importance. 

168.  Spraying  for  the  Control  of  Wild  Morn- 

ine-Glorv  within  the  Fog  Belt. 

169.  1918  Grain  Crop. 

170.  Fertilizing  California  Soils  for  the  1918 

Crop. 

171.  The  Fertilization  of  Citrus. 

172.  Wheat  Culture. 

173.  The    Construction    of    the    Wood-Hoop 

Silo. 

174.  Farm    Drainage   Methods. 


